Ursula Laa

Dr. Ursula Laa

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Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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20 May 2014 in The European Physical Journal C
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Journal Article
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SKSabine Kraml
Sabine Kraml
SKSuchita Kulkarni
Suchita Kulkarni
ULUrsula Laa
Ursula Laa
ALAndre Lessa
Andre Lessa
WMWolfgang Magerl
Wolfgang Magerl
WWWolfgang Waltenberger
Wolfgang Waltenberger
We present a general procedure to decompose Beyond the Standard Model (BSM) collider signatures presenting a \(\mathbb {Z}_2\) symmetry into Simplified Model Spectrum (SMS) topologies. Our method provides a way to cast BSM predictions for the LHC in a model independent framework, which can be directly confronted with the relevant experimental constraints. Our concrete implementation currently focusses on supersymmetry searches with missing energy, for which a large variety of SMS results from ATLAS and CMS are available. As show-case examples we apply our procedure to two scans of the minimal supersymmetric standard model. We discuss how the SMS limits constrain various particle masses and which regions of parameter space remain unchallenged by the current SMS interpretations of the LHC results.

1 January 2018 in Computer Physics Communications
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Journal Article
Closed access
DBD. Barducci
D. Barducci
GBG. Bélanger
G. Bélanger
JBJ. Bernon
J. Bernon
FBF. Boudjema
F. Boudjema
JSJ. Da Silva
J. Da Silva
APA. Pukhov
A. Pukhov

1 June 2018 in Computer Physics Communications
Verified
Journal Article
Closed access
FAFederico Ambrogi
Federico Ambrogi
SKSabine Kraml
Sabine Kraml
SKSuchita Kulkarni
Suchita Kulkarni
ULUrsula Laa
Ursula Laa
ALAndre Lessa
Andre Lessa
WWWolfgang Waltenberger
Wolfgang Waltenberger

1 June 2020 in Computer Physics Communications
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Journal Article
Closed access
FAFederico Ambrogi
Federico Ambrogi
JDJuhi Dutta
Juhi Dutta
JHJan Heisig
Jan Heisig
SKSabine Kraml
Sabine Kraml
SKSuchita Kulkarni
Suchita Kulkarni
MWMatthias Wolf
Matthias Wolf

18 May 2017 in The European Physical Journal C
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Journal Article
Open access
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SKSabine Kraml
Sabine Kraml
ULUrsula Laa
Ursula Laa
KMKentarou Mawatari
Kentarou Mawatari
KYKimiko Yamashita
Kimiko Yamashita
We consider simplified dark matter models where a dark matter candidate couples to the standard model (SM) particles via an s-channel spin-2 mediator, and study constraints on the model parameter space from the current LHC data. Our focus lies on the complementarity among different searches, in particular monojet and multijet plus missing-energy searches and resonance searches. For universal couplings of the mediator to SM particles, missing-energy searches can give stronger constraints than WW, ZZ, dijet, dihiggs, \(t\bar{t}\), \(b\bar{b}\) resonance searches in the low-mass region and/or when the coupling of the mediator to dark matter is much larger than its couplings to SM particles. The strongest constraints, however, come from diphoton and dilepton resonance searches. Only if these modes are suppressed, missing-energy searches can be competitive in constraining dark matter models with a spin-2 mediator.

18 November 2016 in Journal of High Energy Physics
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Journal Article
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SKSabine Kraml
Sabine Kraml
ULUrsula Laa
Ursula Laa
LPLuca Panizzi
Luca Panizzi
HPHugo Prager
Hugo Prager
We assess how different ATLAS and CMS searches for supersymmetry in the \( t\overline{t}+{E}_T^{\mathrm{miss}} \) final state at Run 1 of the LHC constrain scenarios with a fermionic top partner and a dark matter candidate. We find that the efficiencies of these searches in all-hadronic, 1-lepton and 2-lepton channels are quite similar for scalar and fermionic top partners. Therefore, in general, efficiency maps for stop-neutralino simplified models can also be applied to fermionic top-partner models, provided the narrow width approximation holds in the latter. Owing to the much higher production cross-sections of heavy top quarks as compared to stops, masses up to mT ≈ 850 GeV can be excluded from the Run 1 stop searches. Since the simplified-model results published by ATLAS and CMS do not extend to such high masses, we provide our own efficiency maps obtained with CheckMATE and MadAnalysis 5 for these searches. Finally, we also discuss how generic gluino/squark searches in multi-jet final states constrain heavy top partner production.